#include "plotter.h"
#include <QtGui>
#include <cmath>

Plotter::Plotter(QWidget *parent)
    : QWidget(parent)
{
    setBackgroundRole(QPalette::Dark);
    setAutoFillBackground(true);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    setFocusPolicy(Qt::StrongFocus);
    rubberBandIsShown = false;

    zoomInButton = new QToolButton(this);
    zoomInButton->setIcon(QIcon(":/images/zoomin.png"));
    zoomInButton->adjustSize();
    connect(zoomInButton, SIGNAL(clicked()), this, SLOT(zoomIn()));

    zoomOutButton = new QToolButton(this);
    zoomOutButton->setIcon(QIcon(":/images/zoomout.png"));
    zoomOutButton->adjustSize();
    connect(zoomOutButton, SIGNAL(clicked()), this, SLOT(zoomOut()));

    setPlotSettings(PlotSettings());
}

void Plotter::setPlotSettings(const PlotSettings &settings)
{
    zoomStack.clear();
    zoomStack.append(settings);
    curZoom = 0;
    zoomInButton->hide();
    zoomOutButton->hide();
    refreshPixmap();
}

void Plotter::zoomOut()
{
    if(curZoom > 0)
    {
        --curZoom;
        zoomOutButton->setEnabled(curZoom > 0);
        zoomInButton->setEnabled(true);
        zoomInButton->show();
        refreshPixmap();
    }
}


void Plotter::zoomIn()
{
    if(curZoom < zoomStack.count() - 1)
    {
        ++curZoom;
        zoomInButton->setEnabled(curZoom < zoomStack.count() - 1);
        zoomOutButton->setEnabled(true);
        zoomOutButton->show();
        refreshPixmap();
    }
}


void Plotter::setCurveData(int id, const QVector<QPointF> &data)
{
    curveMap[id] = data;
    refreshPixmap();
}

void Plotter::clearCurve(int id)
{
    curveMap.remove(id);
    refreshPixmap();
}

QSize Plotter::minimumSizeHint() const
{
    return QSize(6 * Margin, 4 * Margin);
}


QSize Plotter::sizeHint() const
{
    return QSize(12 * Margin, 8 * Margin);
}

void Plotter::paintEvent(QPaintEvent *)
{
    QStylePainter painter(this);
    painter.drawPixmap(0,0, pixmap);

    if(rubberBandIsShown)
    {
        painter.setPen(palette().light().color());
        painter.drawRect(rubberBandRect.normalized().adjusted(0,0,-1,-1));;

    }

    if(hasFocus())
    {
        QStyleOptionFocusRect option;
          option.initFrom(this);
          option.backgroundColor = palette().dark().color();
          painter.drawPrimitive(QStyle::PE_FrameFocusRect, option);

    }
}


void Plotter::resizeEvent(QResizeEvent *)
{
    int x = width() - (zoomInButton->width() + zoomOutButton->width() + 10);
    zoomInButton->move(x, 5);
    zoomOutButton->move(x + zoomInButton->width() + 5, 5);
    refreshPixmap();
}


void Plotter::mousePressEvent(QMouseEvent *event)
{
    QRect rect(Margin, Margin, width() - 2 * Margin, height() - 2 * Margin);

    if(event->button() == Qt::LeftButton)
    {
        if(rect.contains(event->pos()))
        {
            rubberBandIsShown = true;
            rubberBandRect.setTopLeft(event->pos());
            rubberBandRect.setBottomRight(event->pos());
            updateRubberBandRegion();
            setCursor(Qt::CrossCursor);
        }
    }
}


void Plotter::mouseMoveEvent(QMouseEvent *event)
{
    if(rubberBandIsShown)
    {
        updateRubberBandRegion();
        rubberBandRect.setBottomRight(event->pos());
        updateRubberBandRegion();
    }
}

void Plotter::mouseReleaseEvent(QMouseEvent *event)
{
    if((event->button() == Qt::LeftButton) && rubberBandIsShown)
    {
        rubberBandIsShown = false;
        updateRubberBandRegion();
        unsetCursor();

        QRect rect = rubberBandRect.normalized();
        if(rect.width() < 4 || rect.height() < 4)
            return;
        rect.translate(-Margin, -Margin);

        PlotSettings prevSettings = zoomStack[curZoom];
        PlotSettings settings;

        double dx = prevSettings.spanX() / (width() - 2 * Margin);
        double dy = prevSettings.spanY() / (height() - 2 * Margin);

        settings.minX = prevSettings.minX + dx * rect.left();
        settings.maxX = prevSettings.minX + dx * rect.right();
        settings.minY = prevSettings.maxY - dy * rect.bottom();
        settings.maxY = prevSettings.maxY - dy * rect.top();
        settings.adjust();

        zoomStack.resize(curZoom + 1);
        zoomStack.append(settings);
        zoomIn();
    }
}

void Plotter::keyPressEvent(QKeyEvent *event)
{
    switch(event->key())
    {
      case Qt::Key_Plus :
        zoomIn();
        break;

    case Qt::Key_Minus :
        zoomOut();
        break;

    case Qt::Key_Left :
        zoomStack[curZoom].scroll(-1, 0);
        refreshPixmap();
        break;

    case Qt::Key_Right :
        zoomStack[curZoom].scroll(+1, 0);
        refreshPixmap();
        break;

    case Qt::Key_Down :
        zoomStack[curZoom].scroll(0, -1);
        refreshPixmap();
        break;

    case Qt::Key_Up :
        zoomStack[curZoom].scroll(0, +1);
        refreshPixmap();
        break;

    default:
        QWidget::keyPressEvent(event);
    }
}


void Plotter::wheelEvent(QWheelEvent *event)
{
    int numDegrees = event->delta() / 8;
    int numTicks = numDegrees / 15;

    if(event->orientation() == Qt::Horizontal)
    {
        zoomStack[curZoom].scroll(numTicks, 0);
    }
    else
    {
        zoomStack[curZoom].scroll(0, numTicks);
    }
    refreshPixmap();
}


void Plotter::updateRubberBandRegion()
{
    QRect rect = rubberBandRect.normalized();

    update(rect.left(), rect.top(), rect.width(), 1);
    update(rect.left(), rect.top(), 1, rect.height());
    update(rect.left(), rect.bottom(), rect.width(), 1);
    update(rect.right(), rect.top(), 1, rect.height());
}

void Plotter::refreshPixmap()
{
    pixmap = QPixmap(size());
    pixmap.fill(this, 0, 0);

    QPainter painter(&pixmap);
    painter.initFrom(this);
    drawGrid(&painter);
    drawCurves(&painter);
    update();
}

void Plotter::drawGrid(QPainter *painter)
{
    QRect rect(Margin, Margin, width() - 2 * Margin, height() - 2 * Margin);
    if(!rect.isValid())
        return;

    PlotSettings settings = zoomStack[curZoom];
    QPen quiteDark = palette().dark().color().light();
    QPen light = palette().light().color();

    for(int i = 0; i<= settings.numXTicks; ++i)
    {
        int x= rect.left() + (i * (rect.width() - 1) / settings.numXTicks);
        double label = settings.minX + (i * settings.spanX() / settings.numXTicks);

        painter->setPen(quiteDark);
        painter->drawLine(x, rect.top(), x, rect.bottom());
        painter->setPen(light);
        painter->drawLine(x, rect.bottom(), x, rect.bottom() + 5);
        painter->drawText(x - 50, rect.bottom() + 5, 100, 20, Qt::AlignHCenter | Qt::AlignTop, QString::number(label) );

    }

    for(int j = 0; j<= settings.numYTicks; ++j)
    {
        int y = rect.bottom() - (j * (rect.height() - 1) / settings.numYTicks);
        double label = settings.minY + (j * settings.spanY() / settings.numYTicks);

        painter->setPen(quiteDark);
        painter->drawLine(rect.left(), y, rect.right(), y);
        painter->setPen(light);
        painter->drawLine(rect.left() - 5, y, rect.left(), y);
        painter->drawText(rect.left() - Margin, y - 10, Margin - 5, 20, Qt::AlignRight | Qt::AlignVCenter, QString::number(label));

    }
    painter->drawRect(rect.adjusted(0, 0, -1, -1));
}


void Plotter::drawCurves(QPainter *painter)
{
    static const QColor colorForIds[6] = {

        Qt::red, Qt::green, Qt::blue, Qt::cyan, Qt::magenta, Qt::yellow
    };

    PlotSettings settings = zoomStack[curZoom];
    QRect rect(Margin, Margin, width() - 2 * Margin, height() - 2 * Margin);
    if(!rect.isValid())
        return;

    painter->setClipRect(rect.adjusted(+1, +1, -1 , -1));

    QMapIterator<int, QVector<QPointF> > i(curveMap);
    while(i.hasNext()){

        i.next();

        int id = i.key();
        QVector<QPointF> data = i.value();
        QPolygonF polyline(data.count());

        for(int j=0; j<data.count(); ++j)
        {
            double dx = data[j].x() - settings.minX;
            double dy = data[j].y() - settings.minY;

            double x = rect.left() + (dx * (rect.width() - 1) / settings.spanX());
            double y = rect.bottom() - (dy * (rect.height() - 1) / settings.spanY());

            polyline[j] = QPointF(x, y);
        }

        painter->setPen(colorForIds[uint(id) % 6]);
        painter->drawPolyline(polyline);
    }
}

PlotSettings::PlotSettings()
{
    minX = 0.0;
    maxX = 10.0;
    numXTicks = 5;

    minY = 0.0;
    maxY = 10.0;
    numYTicks = 5;
}

void PlotSettings::scroll(int dx, int dy)
{
    double stepX = spanX() / numXTicks;
    minX += dx * stepX;
    maxX += dx * stepX;

    double stepY = spanY() / numYTicks;
    minY += dy * stepY;
    maxY += dy * stepY;
}

void PlotSettings::adjust()
{
    adjustAxis(minX, maxX, numXTicks);
    adjustAxis(minY, maxY, numYTicks);
}

void PlotSettings::adjustAxis(double &min, double &max, int &numTicks)
{
    const int MinTicks = 4;
    double grossStep = (max - min) / MinTicks;
    double step = std::pow(10.0, std::floor(std::log10(grossStep)));

    if( 5 * step < grossStep)
    {
        step *= 5;

    }
    else if(2 * step < grossStep)
    {
        step *= 2;
    }

    numTicks = int(std::ceil(max / step) - std::floor(min / step));
    if(numTicks < MinTicks)
        numTicks = MinTicks;

    min = std::floor(min / step) * step;
    max = std::ceil(max / step) * step;
}
